1. Field of the Invention
The present invention generally relates to a patient interface for use in a pressure support system that supplies a flow of gas to the airway of a patient, and, in particular, to a patient interface that includes a flexible connecting member that couples a seal member and mask shell to allow angular movement therebetween.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, such as a bi-level pressure that varies with the patient's respiratory cycle or an auto-titrating pressure that varies with the monitored condition of the patient. Typical pressure support therapies are provided to treat a medical disorder, such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), Cheyne-Stokes respiration, or congestive heart failure.
Non-invasive ventilation and pressure support therapies involve the placement of a patient interface, which is typically a nasal or nasal/oral mask, on the face of a patient. The patient interface couples the ventilator or pressure support system with the airway of the patient, so that a flow of breathing gas can be delivered from the flow/pressure generating device to the airway of the patient.
Because such patient interfaces are typically worn for an extended period of time, a variety of concerns must be taken into consideration. For example, in providing CPAP to treat OSA, the patient normally wears the patient interface all night long while he or she sleeps. One concern in such a situation is that the patient interface is as comfortable as possible, otherwise the patient may avoid wearing the interface device, defeating the purpose of the prescribed pressure support therapy. It is also important that the patient interface provide a tight enough seal against the user's face without discomfort. A problem arises in that in order for the mask to maintain a seal without any undue gas leaks around the periphery of the mask, the mask may be compressed against the patient's face with too much force, causing discomfort.
Typically, patient interfaces include a mask shell having a cushion (also referred to as a seal or seal member) attached to the shell. The cushion contacts the surface of the user. The mask shell and cushion are held in place by a headgear that wraps around the head of the user. The patient interface and headgear form a patient interface assembly. A typical headgear includes flexible, adjustable straps that extend from the mask to attach the mask to the patient.
A variety of techniques have been attempted to strike a balance between patient comfort and leak minimization. For example, it is known to form the cushion from a soft material, provide multiple flaps in the cushion, contour the cushion to match the human face, and form the cushion from a material that can be customized to the features of the user. It is also known to provide adjustability for the patient interface on the user, for example, by providing an adjustable forehead assembly. However, these patient interfaces may not meet all the needs of the patient population.